Acral lentiginous melanoma
Template:DiseaseDisorder infobox
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Acral lentiginous melanoma is a kind of skin melanoma. It is also known as subungual melanoma. It is seen on the palms, soles and under the nails.
Pathophysiology
Microscopic Pathology
The microscopic hallmarks are:
- Atypical melanocytes in junctional nests
- dermal invasion
- Desmoplasia
- Hyperplastic epidermis
Epidemiology and Demographics
Age
The average age at diagnosis is between sixty and seventy years.
Race
This is the most common form of melanoma in Asians and Blacks. It also occurs in Caucasians and in young people.
Natural History, Complications, and Prognosis
Any new area of pigmentation or an existing one that shows change should be checked by a dermatologist. If caught early this type of melanoma has a similar cure rate as the other types of superficial spreading melanoma.
Diagnosis
Symptoms
Typical symptoms include:
- longitudinal tan, black, or brown streak on a finger or toe nail (melanonychia striata)
- pigmentation of proximal nail fold
- areas of dark pigmentation on palms of hands or soles of feet
Physical Examination
This type of melanoma occurs on non hair baring surfaces of the body which may or may not be exposed to sunlight.
An example of a subungual melanoma is shown in the image below.
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This is a subungual radial growth phase of acral-lentiginous type with two amelanotic vertical growth phase tumor nodules. Radial growth phase is just beginning to grow onto the cuticle of the nail, displaying a subtle example of "Hutchinson's sign."
References